Intravenous pumping air management systems and methods

ABSTRACT

An intravenous (“IV”) liquid delivery system includes: an IV pump tubing set; a shuttle pump or membrane pump actuator operable with the IV pump tubing set; upstream and downstream valve actuators operable with the IV pump tubing set; the IV pump tubing set including an air removal device; an air detector configured to sense air in the IV pump tubing set; a control unit configured and arranged to (i) open the upstream valve actuator and close the downstream valve actuator to allow the pump actuator to draw liquid into a pump actuation portion of the IV pump tubing set, and (ii) close the upstream valve actuator and open the downstream valve actuator to allow the pump actuator to push liquid out of the pump actuation portion, the system configured to attempt to remove the air via the air removal device while operating the upstream and downstream valve actuators according to (i) and (ii).

PRIORITY CLAIM

This application is a continuation application of, and claims thebenefit of and priority to, U.S. patent application Ser. No. 12/981,152,filed on Dec. 29, 2010, the entire contents of which are incorporatedherein by reference.

BACKGROUND

The present disclosure relates generally to infusion pumping and inparticular to air detection and elimination associated with infusionpumping.

Introduction of air into a patient's bloodstream via infusion pumping ordrug delivery is a well known risk. Internationally recognizedstandards, such as IEC 60601, and recommendations from industry groupssuch as ECRI, call for infusion pumps to stop and alarm upon thedetection of air bubbles of a minimum size, such as in the fifty totwo-hundred fifty micro-liter (“μl”) range. The interruption of drugdelivery, however has its own significant drawbacks, such asinterrupting the nurse or caregiver for the air-in-line event. Theinterruption can impact nursing labor hours and affect the overallprovision of care. Also, the nurse's response can be delayed because ofmore pressing patient issues. There is also a risk of blood streaminfection (“BSI”) due to opening the intravenous (“IV”) system to removethe air.

More importantly, stopping an IV drug infusion can lead to problemsespecially during a critical therapy, in the intensive care unit (“ICU”)or during operating (“OR”) environments, in which patients can beadministered multiple IV medications, some of which are short actingdrugs for which their flow stoppage can lead to blood pressurevariation, arrthymia or other instability. The drugs are critical to theprocedure or therapy being performed, which itself may be critical,leading to a negative situation when the IV pumping is stoppedimmediately after air-in-line detection.

An improved IV pump air management procedure is needed accordingly toavoid interruption of therapy.

SUMMARY

The present disclosure sets forth systems and methods for improvedintravenous (“IV”) pumping air management, which attempt to deliveruninterrupted infusion of critical IV liquids and medications even whenair has entered the infusion line.

A first primary system and method includes an air removal device locatedupstream of the IV pump to prevent air from entering into the pumpportion of the tubing set. In one embodiment, the pump is a shuttle typeinfusion pump, which uses upstream and downstream valves that sequenceto allow medical liquid to be: (i) pulled into an area of the pumptubing set that operates with a shuttle pump actuator and then (ii)expelled from the section of pump tubing set. The air removal device canbe made as part of the pump tubing set and is accordingly made of asuitable medical grade polymer or plastic. The air removal device canalso have a housing positioned in-line with the pump tubing set, be apart of a pumping tubing set itself or be an enlarged diameter sectionof tubing connected in-line with the pump tubing set. The air removaldevice includes a liquid inlet and a liquid outlet and in an embodimentis disposed and arranged with respect to the pump tubing set so that inoperation the liquid inlet resides elevationally above the liquidoutlet.

An air passing but liquid retaining (e.g., hydrophobic) filter islocated or carried by the air removal device at the top of the device,near the liquid inlet. A check valve is located in or carried by the airremoval device in air flow communication with the hydrophobic filter.For example, the check valve could be located between (i) thehydrophobic filter and the external environment or (ii) just upstream ofthe hydrophobic filter. The check valve prevents the IV pump fromdrawing air through the hydrophobic filter into the air removal devicewhen the IV pump is creating negative pressure to pull the drug ormedical liquid from a supply into the pump.

A hydrophilic filter prevents any air in the air removal device frompassing downstream into the pump tubing set. Collected air builds aslight pressure within the air removal device, eventually passingthrough the hydrophobic filter, cracking the check valve and leaving theair removal device and the IV system. Air is removed in a manner suchthat the pumping of the medical liquid or drug is not interrupted.

Liquid for pumping tends to pool at the bottom of the air separationdevice, at its liquid outlet. The liquid passing but air retaining(e.g., hydrophilic) filter is accordingly placed in one embodiment inthe liquid outlet so that air that has not been removed from solution istrapped at the air retaining filter and is not allowed to pass to thepump actuation portion of the pump tubing set. As described in moredetail below, the air removal devices of the present disclosure shouldbe configured and arranged such that they are (i) not position sensitiveor (ii) if position sensitive, arranged so that the hydrophobic membraneremains dry. That is, certain air removal devices described below areconfigured so that air can be removed from the devices regardless oftheir mounted orientation. But other devices described herein can becomeblocked such that they cannot purge when their hydrophobic membranebecomes wet. In this latter situation, the position sensitive devicesare arranged on the infusion pump or elsewhere such that they do notallow the hydrophobic membrane to become blocked.

It is contemplated in one implementation to locate the air separationdevice upstream of the upstream shuttle pump valve in an attempt toallow only degassed medical liquid that has left the air separationdevice to enter the pump actuation portion of the pumping pump tubingset. Other alternative embodiments and structures for the first primaryembodiment are discussed in detail below.

In a second primary embodiment, the air separation device moves the airremoval device downstream of the pump actuator and eliminates the checkvalve, which is not needed because the downstream air removal deviceonly sees positive pressure. The control unit of the infusion pumpsenses that the pump tubing set of this second embodiment has beenloaded into the infusion pump and does not shut down the infusion pumpupon the detection of air by an upstream air detector. The sensor can bepositioned to sense the air removal device itself or a marking, e.g., abarcode on the pump tubing, which indicates the air removal device ispresent.

It is assumed that the downstream air removal device will remove airsensed by an upstream air removal device, however, a downstream airdetector can also be provided. Thus when the upstream air detectordetects air, the systems posts an alarm but does not stop the pump. Ifair is sensed at the downstream air detector, which has not been removedby the air separation device, the control unit shuts the infusion pumpdown via a valve located downstream of the downstream air detector.

If the air elimination device of the second primary embodiment (or anyof the embodiments described herein) is position sensitive, an “airblock” situation can occur. In such a situation, liquid wets thehydrophobic membrane, preventing or blocking air from thereafter beingremoved via the hydrophobic membrane. In such a situation, it iscontemplated (i) to orient the air removal device in a vertical manner(e.g., by vertical placement in the pump housing), such that airmigrates to the top of the air removal device where the hydrophobic ventis located to purge the air, or (ii) to otherwise orient the air removaldevice to direct air bubbles to the hydrophobic membrane or vent.

In a third primary system and method of the present disclosure, air thatis detected is actively purged from the pumping system in a manner suchthat the pumping of the medical liquid or drug is not interrupted. TheIV pump in one implementation is again a shuttle type medical infusionpump. Here, an additional air purge valve is added downstream of thedownstream shuttle pump valve. An air removal device is placed in liquidcommunication with the pump tubing set between the downstream shuttlepump valve and the even further downstream additional air purge valve.The air removal device of this third primary embodiment can include aseparate housing that is teed-off or that otherwise extends from thepump tubing set located between the downstream valves. The housing maysimply be a port that supports the liquid retaining or hydrophobicfilter or membrane. A hydrophilic filter is not needed with the airremoval device of the third primary embodiment.

A bypass line is provided that extends from a point in the tubingbetween the downstream air removal device and the downstream additionalair purge valve back to a point upstream of an air removal device thatitself is upstream of the pump. A bypass valve is provided in the bypassline. Under normal operation when no air is present, the downstreamadditional air purge valve is opened and the bypass valve is closed,allowing fluid to be pumped to the patient.

If air is detected in the pump tubing set, the additional downstream airpurge valve is closed and the bypass valve is opened, creating pressurebetween the shuttle pump actuator and the closed, additional downstreamvalve, and causing air entrained fluid to flow back upstream of thepump. The pressure and recirculation forces air into the air removaldevice and out of a vent or valve, e.g., an air passing but liquidretaining or hydrophobic filter or membrane attached to the air removaldevice. The downstream air purge valve can be closed and the bypassvalve opened for an amount of time or a number of pump-out strokes thatis known or expected to be sufficient to purge air from the system, oruntil an air sensor measurement is “cleared”, after which the air purgevalve is opened and the bypass valve is closed to allow the pressurizedand degassed medical liquid or drug to flow towards the patient.

Multiple configurations of the air eliminating device are possible withthe bypass recirculation of the third to fifth primary embodiment. Theair removal devices are not position sensitive in one preferredembodiment. If the air elimination device is position sensitive, itshould again be oriented in a vertical manner (e.g., located as such byplacement in the pump housing) or be implemented with a configurationthat will direct air bubbles to the hydrophobic element. Also, with anyof the recirculation bypass embodiments, it is contemplated to run theinfusion pump as quickly as possible in the recirculation bypass airelimination mode, so as to minimize the time during which medication isnot delivered to the patient and to remove air as quickly andeffectively as possible.

In a fourth primary embodiment, a bypass recirculation line and bypassvalve are again provided but no hydrophobic filter, hydrophilic filteror check valve is needed. The additional downstream air purge valve ofthe third primary embodiment is also provided. The valved bypass orreturn line is runs again from a point in the main therapy tubingbetween the downstream valves, back to a supply bag or supply container.The supply container is thus connected to two lines, the main therapyline and the return bypass line. When air is detected by an upstream airsensor, the furthest downstream air purge valve actuator closes, thebypass valve actuator opens, the pump actuator and associated valveactuators continue to operate, and air entraining medical fluid isrecirculated back through the supply container. Recirculation can becontrolled via feedback, in which it is continued until the upstream airdetector no longer senses air, or be controlled open loop, e.g., for aperiod of time or number of pump strokes. The downstream air detectoroperates as a fail-safe system shut down detector.

In a fifth primary embodiment, a recirculating bypass line, bypass valveand downstream air purge valve are again provided. Here, like with thethird primary embodiment, the bypass line returns to the main therapytubing instead of to the supply container. Also, a hydrophobic airremoval device is placed either in the main flow therapy tubing or inthe bypass line. In one example, the air removal device is a centripetalair removal device that can be placed anywhere in the bypass line. Whenthe upstream air sensor detects air, the air purge valve actuator closesand the bypass valve actuator opens, while the pump actuator andassociated valve actuators continue to operate. The air entrainingmedical fluid is recirculated, closed loop or open loop as describedherein, until air has been satisfactorily removed from the medicalfluid. The downstream air detector operates again as a fail-safe sensorto shut the system down if needed.

In a sixth primary embodiment, a highly effective hydrophobic airremoval device, described herein as a hydrophobic, air removal dialyzeris located between the downstream pump valve actuator and a downstreamair detector. The efficient hydrophobic air removal device includes ahousing with potted ends that hold long, thin hydrophobic fibers,forming a structure having a look similar to a dialyzer. The housingdefines one or more air vents. Medical fluid possibly entraining airflows through the insides of the hollow hydrophobic fibers. Theelongated geometry and narrow lumens of the fibers and an overallpositive transmembrane pressure tending to push air radially out of thefibers provides a path of resistance for the entrained air radially outof the fibers that is much less than the resistance required to flow allthe way through the fibers. It is accordingly believed that such airremoval device may be efficient enough not to require an accompanyinghydrophilic membrane, air purge valve or bypass path. A downstreamfail-safe system shutdown air sensor is provided in an embodiment incase air does escape through the exit end of the dialyzer-like airremoval device.

There are a number of features applicable to each of the primaryembodiments discussed herein. For example, each of the embodimentsdiscussed herein provides a first air-in-line detector placed upstreamof the pump actuation area of the pump tubing set to detect air prior tothe air reaching the pump. The upstream air sensor and any of the airsensors discussed herein can for example be ultrasonic air detector thatuses ultrasonic waves to non-invasively detect air bubbles flowinginside the tube. For any of the embodiments discussed herein, theupstream air detector may additionally be used with the associatedcontrol unit to integrate the sensed air over time, so that theaccumulated air can be subtracted from an assumed amount of total fluidpumped, which may be assumed by counting pump strokes of known volumes.It is contemplated to use an air detector that can estimate the size ofthe air bubbles so that the air volume can be accumulated. It is alsocontemplated to use multiple air detectors, e.g., spaced ninety degreesfrom each other to detect each of a pair of air bubbles travelingtogether.

Also, a second, downstream air detector may be provided to ensure thatthe system and method has removed the air detected by the upstream airsensor. In particular, the second primary embodiment places thedownstream air detector upstream of a downstream valve actuator asdiscussed below. The other primary embodiments may place a downstreamair detector much closer to the patient. It is contemplated to configurethe control unit such that the pump is allowed to continue to pump thedrug or medication to the patient until the air detected by thisdownstream sensor is calculated to be close to the infusion site basedfor example on a known flowrate, tubing diameter, tubing length andlocation of the activated air detector. Such structure and methodologyagain maximizes the time that the drug is delivered to the patient,while maintaining safety.

Alternative embodiments and structures for the air removal devices aredescribed in detail below, including combinations of the systems andmethods of the primary embodiments.

It is accordingly an advantage of the present disclosure to provideintravenous (“IV”) pump air removal systems and methods.

It is another advantage of the present disclosure to provide air removalsystems and methods that do not require the pump to interrupt therapyfor situations in which air is introduced into an intravenous line.

It is a further advantage of the present disclosure to provide airremoval systems and methods that remove air from the medical liquid ordrug prior to reaching the pump.

It is still another advantage of the present disclosure to provide IVpump air removal systems and methods that actively purge air thattravels downstream of the infusion pump.

It is yet a further advantage of the present disclosure to provide IVpump air removal systems and methods that use a highly efficient in-linehydrophobic air removal device.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic view of one embodiment of an intravenous (“IV”)pumping system and method of the present disclosure having an upstreamair removal apparatus.

FIG. 2 is a schematic view of one embodiment of an IV pumping system andmethod of the present disclosure having a downstream air removalapparatus.

FIG. 3 is a schematic view of one embodiment of an IV pumping system andmethod of the present disclosure having an air removal recirculationbypass apparatus.

FIG. 4 is a schematic view of another embodiment of an IV pumping systemand method of the present disclosure having an alternative air removalrecirculation bypass apparatus.

FIG. 5 is a schematic view of a further embodiment of an IV pumpingsystem and method of the present disclosure having a further alternativeair removal recirculation bypass and air removal device.

FIG. 6 is a schematic view of one embodiment of an IV pumping systemhaving an inline hydrophobic, air removing dialyzer.

FIG. 7A is a sectioned front elevation view of one embodiment of thehydrophobic, air removing dialyzer or device of FIG. 6.

FIG. 7B is a sectioned end view taken along line VIIB-VIIB of FIG. 7A.

DETAILED DESCRIPTION System Generally

Referring now to the drawings and in particular to FIG. 1, intravenous(“IV”) pumping system 10 illustrates one primary embodiment of the airremoval apparatus and methodology of the present disclosure. IV pumpingsystem 10 pumps a medical liquid, drug or medicament from a supply 30,through a tube 18, to a patient 80, via a patient catheter, needle orcannula (catheter 82 used hereafter to represent all) 82. Tube 18 and anair removal device, such as device 60 of FIG. 1, form part of oneembodiment of an IV pump tubing set 40. Tubing set 40 in an embodimentis then connected to supply 30 and catheter 82 to form an overalldisposable component of system 10. Tube 18 as illustrated is loaded intoIV pumping system 10, so that IV pumping system 10 can pull liquid fromsupply 30 and move the liquid in a controlled manner through tube 18,catheter or cannula 82 to patient 80.

IV pumping system 10 includes a control unit 12. Control unit 12includes one or more processors, such as supervisory processor, whichcontrols one or more delegate processors, which in turn controls variousaspects of IV pumping system 10. Control unit 12 can, for example,employ a safety or monitoring processor, which ensures that thesupervisory processor and delegate control processors are operatingproperly. The processors operate with one or more memory, which is alsopart of control unit 12. As shown, control unit 12 operates with orcontrols a user interface 14. The user interface 14 displays informationto the patient or operator and also allows the patient or operator toenter information from the user interface into control unit 12. To thatend, user interface 14 can operate with a touch screen overlay or withone or more electromechanical input device, such as a membrane switch.

User interface 14 enables the operator to command control unit 12 tocontrol IV pumping system 10 to run: (i) a continuous mode in which pump10 delivers liquid via tubing 18 to achieve a desired volume at a singleflowrate; (ii) an auto-ramp mode in which IV pumping system 10 deliversliquid from supply 30 at a rate that gradually increases to a threshold,remains at the threshold rate for a prescribed time, and then graduallydecreases; (iii) an intermediate mode in which IV pumping system 10delivers discrete liquid volumes spaced over relatively long periods oftime, such as a bolus or volume every three hours; (iv) a custom mode inwhich IV pumping system 10 delivers a unique infusion rate at differenttime intervals; (v) a patient-controlled analgesic (“PCA”) mode duringwhich patient 80 presses a button causing IV pumping system 10 toperiodically infuse a bolus of analgesic into the patient; and (vi) aclosed loop therapy mode based on physiological sensor feedback. Userinterface 14 can display one or more features and parameters pertinentto the air management systems operation, such as an amount of airdetected and removed from pump tubing set 40 and the therapy time or logof air removed events.

To provide the various modes of delivery, control unit 12 operates anupstream valve or occluder 16 a, a downstream valve or occluder 16 b anda pump actuator 20. Valves or occluders 16 a and 16 b are shown as beingelectrically actuated pinch or solenoid valves but can alternatively bepneumatically or pneumatic/mechanically actuated membrane valves orpillow valves. To this end, while the IV pump tubing set 40 is shown touse tube 18 for valving and pumping, a pumping and valving cassette,e.g., for pneumatic or pneumatic/mechanical operation, can be usedalternatively. Control unit 12, user interface 14, valve actuators 16 aand 16 b, and pump actuator 20 in the illustrated embodiment are housedin pump housing 22.

In one embodiment, the systems and methods described herein operate witha shuttle pump type of pump actuator. One suitable shuttle pump type ofpump actuator is set forth in U.S. Pat. No. 5,842,841, entitled,“Volumetric Infusion Pump With Transverse Tube Loader”, assigned to theassignee of the present disclosure, the entire contents of which areincorporated herein by reference and relied upon. Other embodiments ofthe systems and methods of the present disclosure, however, can usevolumetric membrane type pumps, peristaltic or other types of rollerpumps.

With a shuttle pump or volumetric membrane pump, to pump a known volumeof drug or medicament, control unit 12 causes valve or occluder 16 a topinch or compress an upstream valve portion 18 a of tubing 18 upstreamof pump actuator 20. Control unit 12 also causes valve or occluder 16 bto open and at the same time or slightly thereafter cause pump actuator20 to compress tubing 18 at pump actuation portion 18 c, forcing a knownvolume of liquid residing in tubing 18 through downstream valve portion18 b of tubing 18, towards catheter or cannula 82 and patient 80. Theknown volume of liquid is set by a length l_(actuator) of the clampingportion of the pump actuator 20 multiplied by an internalcross-sectional area of tubing 18 at pump actuation portion 18 c.

After the drug or medicament volume is delivered to patient 80, controlunit 12 causes downstream valve or occluder 16 b to close downstreamvalve portion 18 b and simultaneously or slightly thereafter open valveactuator 16 a, allowing medical liquid from supply 30 to flow throughdownstream valve portion 18 b of tubing 18 into pump actuation portion18 c of tubing 18. Pump actuator 20 is simultaneously or slightlythereafter opened to indirectly or actively decompress tubing portion 18a, creating a vacuum, which draws the drug or medicament into pumpingportion 18 c within the length l_(actuator) of the clamping portion ofpump actuator 20. Gravity may help feed the medical liquid or drug fromsupply 30 into pumping portion 18 c of tubing 18, however, it is nottypically relied upon.

Control unit 12 repeats the above-described valve sequencing and pumpactuation until a desired total amount of medical liquid is deliveredvia cannula or catheter 82 to patient 80. The total volume is equal tothe individual pump volumes of pumping portion 18 c multiplied by thenumber of pump-out strokes. The rate at which valves 16 a and 16 b areswitched in combination with the actuation of pump actuator 20 sets therate at which the drug, medicament or medical liquid is delivered topatient 80.

First Primary Embodiment

In system 10 of FIG. 1, an air removal device 60 is located upstream ofvalve actuator 16 a and corresponding upstream valve portion 18 a oftubing 18. Air removal device 60 may be located along IV pump tubing set40, such that the device resides inside or outside of pump housing 22.Air removal device 60 includes its own housing 62, e.g., of a rigidconstruction, which in one embodiment is made of a medical gradepolymer, which can be relatively inexpensive, especially for the case inwhich air removal device 60 is integral with and disposed with IV pumptubing set 40. Air removal device 60 may be made for example of the samematerial as tubing 18, such as, silicone, polyvinyl chloride (“PVC”) orother materials whose selection can be optimized for a particular use.

Housing 62 can be a cylindrical, rectangular or other suitably shapedcontainer and be made of a semi-rigid or rigid material such aspolycarbonate and acrylonitrile butadiene styrene (“ABS”). Housing 62 inone preferred embodiment is cylindrical with smooth geometrictransitions to route liquid without causing air entrainment in thefluid. Housing 62 can be a larger diameter section of tubing than tubing18. Housing 62 can further alternatively be a section of tubing having asame diameter as tubing 18. Still further alternatively, housing 62 hasa “Y” or “T” extension protruding from housing 62 at an angle to orperpendicular from the axis of tubing 18. Housing 62 in one embodimentis configured to be easily sterilized using the appropriate materialsand methods, such as gamma radiation or electron beam sterilization.

Housing 62 of air removal device 60 includes a liquid inlet 64 and aliquid outlet 66. An air collection portion 68 of housing 62 resides inthe illustrated embodiment adjacent to liquid inlet 64. In use, aircollection portion 68 will operate even if completely filled withliquid. Alternatively, air collection portion 68 may reside at the endof a “Y” or “T” extension (not illustrated) protruding from a main bodyportion of housing 62. A liquid collection portion 70 of housing 62resides adjacent to liquid outlet 66.

As shown in the illustrated embodiment, air removal device 60 in oneembodiment is configured such that air collection portion 68 resides, inoperation, elevationally or vertically above liquid collection portion70. In operation, medical liquid or drug flows from supply 30, throughliquid inlet 64 of housing 62 and settles in liquid collection portion70. Air rises through the liquid of liquid collection portion 70,degassing out of solution and settling within air collection portion 68of housing 62 before being forced out of air removal device 60.

An air passing but liquid retaining filter 74, e.g., a hydrophobicfilter, is fitted to or formed with housing 62 at the air collectionportion 68 of air removal device 60. One suitable hydrophobic materialfor hydrophobic filter 74 is a “super hydrophobic” filter, which can bea polyvinylidene fluoride (“PVDF”) material grafted with a fluorinatedmonomer, such as a REPEL™ filter made by Millipore, 290 Concord Road,Billerica, Mass. 01821. Filter 74 in one advantageous embodiment islocated below the supply as far as possible and as close as possible tothe pump, so as to maximize gravity head pressure to operate rack openthe normally closed one-way check valve 76.

While it is desirable to align housing 62 of air removal device 60 withpump housing 22 vertically as shown in FIG. 1, such that liquidretaining filter 74 is located elevationally above outlet 66, it is alsodesirable to design the geometry of the housing and the placement of thefilters such that the device is as position insensitive as possible. A“super hydrophobic” filter 74 is more position insensitive than one thatis not because it is less prone to wetting out.

Another possibility for making liquid retaining filter 74 more positioninsensitive is to use a filter provided by Ivax Corporation, Miami Fla.,which combines a hydrophilic element (discussed below) with ahydrophobic element. A further possibility for making liquid retainingfilter 74 more position insensitive is to use a device provided byGelman, Inc, Ann Arbor Mich., Part Number 6164420, which is a devicethat sandwiches two liquid retaining (hydrophobic) filters 74 around asingle hydrophilic element (discussed below).

In still another alternative embodiment, housing 62 is structured toprovide an annular, circular or spherical liquid path around liquidretaining filter 74. Assuming the flowrate (e.g., a bypass orrecirculation flowrate as shown below in FIG. 5) of the medical liquidto be sufficient, such as 1000 to 4000 milliliters/hour, the heavierliquid tends to be pushed by centripetal force outwardly along theannular or circular liquid path, causing the air to migrate inwardstowards liquid retaining filter 74. It is contemplated that liquidretaining filter 74 could extend horizontally or vertically (or even atsome angle) relative to the annular or circular liquid path, so as tomake air removal device 60 less position sensitive.

In the illustrated embodiment, a one-way check valve 76 is provided withhousing 62 just outside of liquid retaining filter 74. Alternatively,liquid retaining filter 74 is provided with housing 62 just outside ofone-way check valve 76. Check valve 76 can be a normally closed one-wayduckbill check valve as shown in FIG. 1, a spring-loaded ball valve or aspring-loaded flapper valve. For example, housing 62 can provide anaperture to which liquid retaining filter 74 is abutted against theinside of the housing. A spring-loaded flap is provided on the outsideof the aperture and housing 62. Positive pressure forces the flap opento relieve air through liquid retaining filter 74. Negative pressureinside housing 62 and the spring force (e.g., due to a natural bias of aliving hinge connecting the flap to housing 62) seals the flap closedagainst the outside of housing 62. In any case, check valve 76 preventsair from being pulled into housing 62 when pump actuator 20 createsnegative pressure in the fill portion 18 c of tubing 18.

In an embodiment, check valve 76 requires a low cracking pressure of,e.g., on the order of ten inches of water pressure. Suitable checkvalves are provided by Nipro Medical Corporation, 3150 NW 107th Avenue,Miami, Fla. 33172. The cracking pressure may be reached naturally due tothe head height of the fluid in the supply container, with air buildingwithin air collection portion 68 or may occur with the aid of upstreamcollection valve 16 a closing, forcing a small amount of medical liquidback towards air removal device 60. Check valve 76 as discussed preventsair from being pulled into air removal device 60 through liquidretaining filter 74, especially when pump actuator 20 opens to create anegative pressure within housing 62.

In the illustrated embodiment, a liquid passing but air retaining filter78, e.g., a hydrophilic filter, is fitted to or formed with housing 62at or near the liquid outlet 66 to prevent air from exiting thoughoutlet 66 into downstream tubing 18. Suitable air retaining filters 78can again be obtained for example from Millipore, 290 Concord Road,Billerica, Mass. 01821, e.g., MF-Millipore™ membranes, MilliporeExpress® membranes and PVDF membranes. Filter 78 separates the air fromthe liquid drug, so that the air can be collected in air collectionportion 68 and forced out of air removal device 60 through liquidretaining filter 74 and check valve 76 or vice versa.

In the illustrated embodiment, retaining filter 78 is shown as a flatsheet. In an alternative embodiment, hollow fiber dialyzer or hemofiltertype microporous membranes are provided and are looped such that bothends of each hollow fiber are encased into a potting material placed inoutlet 66. The potting material encases only the exterior of the hollowfibers; the lumens of the hollow fibers are not encased and are incommunication with outlet 66. Thus any fluid making its way through theair removal device 60 has to flow through the pores of one of the loopedhollow fiber membranes. The microporous membranes when wetted howeverblock air from migrating through the membranes, as is known, therebyacting to separate or degas the air from the liquid drug. Only theliquid medical fluid can therefore make its way through the air removaldevice 60 and into pump tubing 18.

It is contemplated to size housing 62 such that air collection portion68 is large enough to collect all air degassed by hydrophilic or airretaining filter 78. Here, liquid retaining filter 74 and check valve 76may not be needed.

In system 10 of FIG. 1, an air detector 72, is placed downstream of airremoval device to detect any air that for some reason is not removedfrom solution and enters pump tubing 18. Air sensor 72 can be anon-invasive ultrasonic air sensor, such as those described in U.S. Pat.Nos. 4,607,520, 4,651,555 and 7,661,293. In the illustrated embodiment,air sensor 72 is located upstream of valve actuation portion 18 a oftubing 18, so that valve 16 a can be clamped if air is detected prior tothe air entering pump actuation portion 18 c of tubing 18. Air sensor 72is located alternatively (or a second air sensor is added) downstream ofvalve actuation portion 18 c of tubing 18 as a last chance check to makesure pumping is stopped if air that is about to go to the patient isdetected.

Second Primary Embodiment

Referring now to FIG. 2, system 110 is an alternative air removal systemto system 10. System 110 is similar in many respects to system 10 ofFIG. 1 and like structures are provided with the same element numbers.System 110 provides upstream and downstream air detectors 72 a and 72 b,respectively. Upstream air removal device 60 is not used and instead adownstream air removal device 160 is provided, which includes a housing162 (made of any of the materials for housing 62) having a liquidretaining filter 74, such as a hydrophobic filter, and an air retainingfilter 78, such as a hydrophilic filter. Air removal device 160 may beposition sensitive, that is, hydrophobic filter 74 may be prone tobecoming wetted, causing an air block. In such a case, air removaldevice 160 is mounted vertically as shown, such that liquid retainingfilter 74 resides at the top of housing 162.

Air retaining filter 78 separates air from the liquid and liquidretaining filter 74 vents the air to atmosphere. Because downstreamtubing 18 b is never intended to be under negative pressure, the checkvalve 76 of FIG. 1 is not needed. However, if desired, a check valvecould be added to air removal device 160 as an additional safetymeasure. A further downstream air purge valve actuator 16 ds, operablewith downstream pump tubing portion 18 ds, is added in one embodiment.Downstream valve actuator 16 ds also communicates with control unit 12.

In the illustrated embodiment, a sensor 120, such as a capacitive orinductive magnetic sensor, an optical sensor, or an electro-mechanicalsensor, in communication with and possibly powered by control unit 12,is located within housing 22 so as to sense or not sense the presence ofair removal device 160. In an alternative embodiment, sensor 120 is areader that reads a marking 118 (shown in FIG. 2). Marking 118 can be abarcode or radio frequency identification (“RFID”) tag located on eithertubing 18 or housing 162 that is read by a suitable reader 120, such asa barcode or RFID reader. Marking 118 identifies pump tubing set 140 asone that does or does not contain air removal device 160.

Sensor or reader 120 communicates data or electrical signals withcontrol unit 12, letting control unit 12 know that an air removal device160 is in place. Control unit 12 is likewise programmed to know that airsensed at upstream air detector 72 a is not to be taken as an event thatshuts down system 110, e.g., closes furthest downstream valve actuator16 ds, shuts down pump actuator 20 and/or closes one or both of valveactuators 16 a and 16 b. That is, it is expected that air removal device160 will remove air sensed at air detector 72 a.

If air is sensed at downstream detector 72 b, however, then control unitcloses furthest down stream valve actuator 16 ds so as to prevent airfrom reaching patient 80. Control unit 12 can likewise shut down pumpactuator 20 and close one or both of valve actuators 16 a and 16 b. If(i) sensor 120 does not sense air removal device 160, (ii) if thealternative marking 118 otherwise indicates that pump tubing set 140 isnot one that includes an air removal device 160, or if (iii) in thealternative marking embodiment no marking 118 is detected at all,control unit 12 is programmed to instead shut down the pump and valveactuators when air is detected at upstream air detector 72 a.

Third Primary Embodiment

Referring now to FIG. 3, system 210 illustrates a first alternativeembodiment for an IV pumping system and method having air removalmanagement using a bypass return line. System 210 pumps medical liquidin the same way, using the same apparatuses housed in pump housing 22operating with an IV pump tubing set 240, including all alternatives forthese apparatuses discussed herein.

System 210 also includes an air removal device 260. Air removal device260 includes a body 262, which in the illustrated embodiment is a “T”off of main therapy flow line 18. Body 262 is alternatively a “Y” off ofmain therapy flow line 18, a larger diameter cylindrical or rectangularhousing, a larger diameter piece of tubing, or a piece of tubing havinga same diameter as tubing 18. Body 262 includes, forms or otherwisehouses an air passing but liquid retaining filter 74, e.g., ahydrophobic filter. Air passing but liquid retaining filter 74 can be ofany of the types described herein. Air removal device 260 is eitherposition insensitive or mounted such that liquid retaining filter 74does not become wetted.

System 210 further includes a bypass line 18 by and corresponding bypassvalve actuator 16 by. Bypass line 18 by branches off of main tubing line18 from a point between air removal device 260 and air purge valveactuator 16 ap and returns fluid to main tubing line 18 upstream ofupstream air sensor 72 a. Air removal device 260 can be placedalternatively in bypass line 18 by.

Air removal device 260 is located in, e.g., formed with or connected to,tube 18 of IV pump tubing set 240 between downstream valve actuator 16b/downstream valve portion 18 b of tube 18 and a further downstream, airpurge valve actuator 16 ap, which operates with a corresponding portionof tubing 18 ap. Bypass valve actuator 16 by and air purge valveactuator 16 ap, like the other valve and pump actuators describedherein, are controlled by control unit 12 and can be of any of the typesdescribed above for valve actuators 16 a or 16 b. Control unit 12 alsopowers and receives signals from upstream air sensor 72 a and downstreamair sensor 72 b. Air sensors 72 a and 72 b can again be non-invasiveultrasonic air sensors, such as those described in U.S. Pat. Nos.4,607,520, 4,651,555 and 7,661,293.

During normal pumping operation, if upstream air sensor 72 a detects airin tubing 18, an appropriate signal is sent to control unit 12. Controlunit 12, which maintains air purge valve actuator 16 ap in an open,e.g., energized state, and bypass valve actuator 16 by in a closed,e.g., un-energized, state during normal pumping operation, closes, e.g.,un-energizes, air purge valve actuator 16 ap and opens, e.g., energizes,bypass valve actuator 16 by when air sensor 72 a senses air. When airpurge valve actuator 16 ap is closed and bypass valve actuator 16 by isopened, pumping valve actuators 16 a and 16 b and pump actuator 20perform at least one pump-out stroke and in an embodiment a series offull pumping strokes. This action circulates air entraining medicalfluid through main flow tubing 18 and bypass line 18 by to remove airthrough air removal device 260.

In one embodiment, control unit 12 is configured to monitor air sensor72 a and maintain the bypass valve and air purge pumping state until airsensor 72 a indicates that the main flow of medical fluid no longerentrains air. Here, air sensor 72 a is used as a feedback provider tocontrol unit 12. Control unit 12 is alternatively configured to runopen-loop and maintain this air purge recirculation state for an amountof time or number of pump strokes that is known or expected, e.g.,determined empirically, to satisfactorily drive air out of air removaldevice 260. Downstream air detector 72 b may again be provided to ensurethat air has been removed once air purge valve actuator 16 ap is openedto resume pumping and to shut system 210 down if air detector 72 bsenses air.

It is expected that because air removal device 260 is not typicallyunder negative pressure in its location between pump portion 18 c andportion 18 ap, that air removal device 260 does not need a check valveas provided above for system 10. If desired however, a check valve canbe provided.

As discussed above, it is also contemplated to provide combinations ofthe systems described herein. For example, in FIG. 3 air removal device60 of systems 10 could be provided in addition to air removal device 260and air purge valve actuator 16 ap. Here, air removal device 60 isprovided to capture and purge air before the air reaches upstream sensor72 a. If air somehow migrates past first air removal device 60, thensecond air removal device 260, valve actuators 16 a and 16 b, and airpurge valve actuator 16 ap operate as described to eliminate thedownstream sensed air. Likewise, air removal device 160 of system 110could be provided as a safety in case air removal device 60 did notremove all air.

Fourth Primary Embodiment

Referring now to FIG. 4, system 310 illustrates another alternativeembodiment for an IV pumping system and method having air removalmanagement. System 310 pumps medical liquid in the same way, using thesame apparatuses housed in pump housing 22 operating with an IV pumptubing set 340, including all alternatives for these apparatusesdiscussed herein.

System 310 in the illustrated embodiment does not include an air removaldevice having a hydrophobic and/or hydrophilic filter as do the systemsabove. System 310 does provide the third air purge valve actuator 16 apdescribed above in connection with system 210 of FIG. 3, which operateswith a corresponding portion of tubing 18 ap. Control unit 12 of system310 also powers and receives signals from upstream air sensor 72 a anddownstream air sensor 72 b. Air sensors 72 a and 72 b can again benon-invasive ultrasonic air sensors, such as those described in U.S.Pat. Nos. 4,607,520, 4,651,555 and 7,661,293.

IV pump tubing set 340 includes a bypass line 18 by, which returns froma point in the main flow tubing 18 between valve portion 18 b and valveportion 18 c to fluid supply 30. In the illustrated embodiment, bypassline 18 by is coupled with the main supply line 18 via a dual lumenspike 24 to simultaneously pierce or otherwise make fluid communicationwith fluid supply 30. Bypass line 18 by enables air entraining medicalfluid to be returned to fluid supply 30, so that the air can becollected at the top of the fluid supply.

An additional bypass valve actuator 16 by is provided and controlled bycontrol unit 12. Bypass valve actuator 16 by as illustrated occludes oropens a portion of bypass line 18 by.

During normal pumping operation, if upstream air sensor 72 a detects airin tubing 18, an appropriate signal is sent to control unit 12. Controlunit 12, which maintains air purge valve actuator 16 ap in an open,e.g., energized state, and bypass valve actuator 16 by in a closed,e.g., un-energized, state during normal pumping operation, closes, e.g.,un-energizes, air purge valve actuator 16 ap and opens, e.g., energizes,bypass valve actuator 16 by when air sensor 72 a senses air. When airpurge valve actuator 16 ap is closed and bypass valve actuator 16 by isopened, pumping valve actuators 16 a and 16 b and pump actuator 20perform at least one pump-out stroke and in an embodiment a series offull pumping strokes. This action circulates the air entraining medicalfluid through main tubing 18, bypass line 18 by and fluid supply 30.

Control unit 12 is configured to monitor air sensor 72 a and maintainthe bypassing valve and air purge pumping state until air sensor 72 aindicates that the medical fluid does not have air. In this instance,air sensor 72 a is used as a feedback provider to control unit 12Control unit 12 is alternatively configured to run open-loop andmaintain this air purge recirculation state for an amount of time ornumber of pump strokes that is known or expected, e.g., determinedempirically, to satisfactorily drive air back to fluid supply 30.Downstream air detector 72 b may again be provided to ensure that airhas been removed once air purge valve actuator 16 ap is opened to resumepumping and to shut system 310 down if air is detected. Air removaldevice 60 of system 10 could again be added upstream of air sensor 72 ato attempt to eliminate air before triggering the bypass purge sequence.

Fifth Primary Embodiment

Referring now to FIG. 5, system 410 illustrates another bypassembodiment for an IV pumping system and method having air removalmanagement. System 410 pumps medical liquid in the same way, using thesame apparatuses housed in pump housing 22 operating with an IV pumptubing set 440, including all alternatives for those apparatusesdiscussed herein.

IV pump tubing set 440 includes a bypass line 18 by, which returns froma point in the main flow tubing 18 between valve portion 18 b and valveportion 18 c, not to fluid supply 30 as with system 310, but insteadback to main flow tubing 18, upstream of air sensor 72 a. Here, bypassline 18 by enables air entraining medical fluid to be recirculated pastair sensor 72 a until it is removed from system 410.

In the illustrated embodiment, a centripetal air/fluid separation device460 is placed in bypass line 18 by. Air separation device 460 isstructured to cause an annular or circular liquid path of fluid to flowaround hydrophobic or liquid retaining filter 74. Assuming the flowrateof the air-entraining medical liquid to be sufficient, such as 1000 to4000 milliliters/hour, the heavier liquid tends to be pushed bycentripetal force outwardly along an annular, circular or sphericalliquid path, causing the air to migrate inwards towards liquid retainingfilter 74. Liquid retaining filter 74 is positioned relative to theannular or circular liquid path, so as to make centripetal air/fluidseparation device 460 less position or orientation sensitive. Air/fluidseparation device 460 can be placed alternatively in main flow tubing18. Air/fluid separation device 460 removes sensed air from therecirculation bypass loop through main flow line 18 and bypass flow line18 by.

During normal pumping operation, if upstream air sensor 72 a detects airin tubing 18, an appropriate signal is sent to control unit 12. Controlunit 12, which maintains air purge valve actuator 16 ap in an open,e.g., energized state, and bypass valve actuator 16 by in a closed,e.g., un-energized, state during normal pumping operation, closes, e.g.,un-energizes, air purge valve actuator 16 ap and opens, e.g., energizes,bypass valve actuator 16 by when air sensor 72 a senses air. When airpurge valve actuator 16 ap is closed and bypass valve actuator 16 by isopened, pumping valve actuators 16 a and 16 b and pump actuator 20perform at least one pump-out stroke and in an embodiment a series offull pumping strokes. This action circulates air entraining medicalfluid through main flow tubing 18 and bypass line 18 by to remove airthrough air removal device 460.

In one embodiment, control unit 12 is configured to monitor air sensor72 a and maintain the bypassing valve and air purge pumping state untilair sensor 72 a indicates that the main flow medical fluid does not haveair. Here, air sensor 72 a is again used as a feedback provider tocontrol unit 12. Control unit 12 is alternatively configured to runopen-loop and maintain this air purge recirculation state for an amountof time or number of pump strokes that is known or expected, e.g.,determined empirically, to satisfactorily drive air out of air/fluidseparation device 460. Downstream air detector 72 b may again beprovided to ensure that air has been removed once air purge valveactuator 16 ap is opened to resume pumping and to shut system 410 downif the system senses air. Air removal device 60 of system 10 could againbe added upstream of air sensor 72 a to attempt to eliminate air beforetriggering the bypass purge sequence.

For any of the recirculation embodiments of FIGS. 3 to 5, it iscontemplated for control unit 12 to be programmed to run the infusionpump actuator 20 and associated valve actuators 16 a and 16 b as quicklyas possible when in the air purge recirculation or bypass mode. By doingso, the time that the drug or medication is not being delivered to thepatient is minimized and air is removed as quickly and effectively aspossible.

Sixth Primary Embodiment

Referring now to FIGS. 6, 7A and 7B, system 510 illustrates anotherembodiment for an IV pumping system and method having air removalmanagement. System 510 pumps medical liquid in the same way, using thesame apparatuses housed in pump housing 22 operating with an IV pumptubing set 540, including all alternatives for those apparatusesdiscussed herein.

System 510 is similar in some respects to system 110 of FIG. 2. System510 can provide a sensor 512, which operates with control unit 12 in thesame way as does reader 120 of system 110 (which can be used with system510 instead of sensor 512). Here, sensor 512, a proximity, optical orother sensor, senses the presence of an air removal device 560. Ifsensor 512 senses air removal device 560, then upstream air detector 72a is used as described below. If sensor 512 does not sense air removaldevice 560, then upstream air detector 72 a is used to shut down system510 when air detector 72 a detects air. Alternatively, sensor 512 is notprovided.

Systems 10 and 110 use hydrophobic filters to stop air flow for airremoval. Systems 210, 310 and 410 provide a separate air purge valveactuator 16 ap to stop main flow through tubing 18, so that air can bepurged before being delivered to patient 80. System 510 does not use airpurge valve actuator 16 ap and relies instead on the path of leastresistance through air removal device 550 to effectively urge air out ofthe device. Downstream air sensor 72 b is provided such that if air isable to escape from air removal device 550 in main flow tubing 18,system 510 shuts down pump actuator 20 and closes one or both of valveactuators 16 a and 16 b. Upstream sensor 72 a is used as an earlywarning air detection device and to allow control unit 12 to integratethe amount of air that passes through tubing 18 during treatment, sothat control unit 12 can subtract out the integrated or accumulated airto improve the accuracy of total volume of medical fluid pumped.

FIGS. 7A and 7B illustrate sectioned front elevation and end views,respectively, of air removal device 560, which may be likened to ahydrophobic, air removing dialyzer. Air removal device 560 includes ahousing 562, which may be made of any of the medical grade plastic orsynthetic materials discussed herein. Housing 562 defines a fluid inlet564 and a fluid outlet 566. Housing 562 also includes a larger diametercentral portion 568. Larger diameter central portion 568 includes ordefines one or more air vent 570. Potted ends 572 a and 572 b are sealedto the inlet and outlet ends of larger diameter central portion 568.Potted ends 572 a and 572 b are made of a dialyzer potting material,such as polyurethane. Plural hydrophobic hollow fibers 574 extendthrough and are held sealingly in place by potted ends 572 a and 572 b.

Hydrophobic hollow fibers 574 are can be made of polyolefins, such aspolyethylene or polypropylene. One suitably sized fiber has an averageouter diameter of about two-hundred microns and a wall thickness ofabout thirty microns.

Medical fluid potentially having entrained air enters inlet 564 ofhousing 562 of air removal device 560. The inlet medical fluid enters aninlet header space 576 before being forced through the inside of one ofhollow hydrophobic fibers 574. It is contemplated to provide many hollowfibers 574, such that the cumulative inner diameter area of hollowfibers 574 when compared to the inner diameter area of tubing 18 doesnot create an undue pressure drop across air removal device 560. Air isremoved through air vent 570 from the medical fluid while flow throughfibers 574 along larger diameter central portion 568. Purged medicalfluid then leaves hollow fibers 574 and gathers in an outlet headerspace 578 before leaving air removal device 560 through outlet 566. Thepurged medical fluid is then allowed to flow to patient 80.

One primary vehicle forcing air to leave hollow hydrophobic fibers 574is least resistance or opportunity. That is, the length of hollowhydrophobic fibers 574 is so much greater than the inner diameter of thefibers that the path of least resistance for an air bubble is to travelradially out of the of hollow hydrophobic fiber 574 as opposed totraveling all the way longitudinally through the fiber. Another way oflooking at the mechanism or vehicle is that hollow hydrophobic fibers574 provide air bubbles with so many opportunities, in close proximityto the fiber walls, to leave hydrophobic fibers 574, that it becomeshighly unlikely that any given air bubble will not take one of theopportunities to leave the fiber radially and instead flow al the waythrough the length of the fiber.

Another primary vehicle forcing air to leave hydrophobic fibers 574 ispositive transmembrane pressure. Purged air leaves housing 562 throughone or more vent 570. Although air pressure may build outside of hollowhydrophobic fibers 574 and within housing 562, a positive transmembranepressure gradient will still exist within the device, tending to pushthe lighter air within the medical fluid towards the inner walls offibers 574. It is accordingly believed that air removal device 560 maybe effective enough so as not to require a hydrophilic filter forblocking air, or a downstream air purge valve for stopping temporarilythe flow of medical fluid, as has been described with various ones ofthe above systems. Also, the positive pressure placement of device 560within system 510 should preclude the need for a check valve. Further,it is contemplated, as before, to combine features of the other systemsif desired, such as a system 10 air removal device 60 upstream of airdetector 72.

It should be appreciated that all systems 10, 110, 210, 310, 410 and 510remove air from tubing 18 and IV pump tubing set 240 without prolonged(or any) interruption of the pumping of the drug, medicament or medicalliquid to patient 80. Systems 10, 110 and 510 are in essence blind tothe pumping and vice-versa. Systems 210, 310 and 410 stop pumping themedical liquid, medicament or drug momentarily, and without interruptingthe operation of valve actuators 16 a and 16 b and pump actuator 20, topurge air but do not send the system into an alarm state or require aprolonged stoppage of drug delivery.

All systems 10, 110, 210, 310, 410 and 510 are provided with an upstreamair detector 72 (system 10) or 72 a (remaining systems) placed upstreamof the pump actuation area of the pump tubing set to detect air prior tothe air reaching the pump. The upstream air sensor 72 and 72 a mayadditionally be used with control unit 12 to integrate the sensed airover time, so that the accumulated air can be subtracted from an assumedamount of total fluid pumped. With shuttle type pump actuator 20, volumeof fluid pumped by counting pump strokes of known volumes, the volumesknown via known l_(actuator) and the known internal diameter of pumptubing section 18 c. It is contemplated to use an air detector that canestimate the size of the air bubbles so that the air volume can beaccumulated. It is also contemplated to use multiple air detectors,e.g., spaced ninety degrees from each other to detect each of a pair ofair bubbles traveling together.

Systems 110, 210, 310, 410 and 510 also include a second, downstream airdetector 72 b provided to ensure that the associated system and methodhas removed the air detected by the upstream air sensor. System 10 canalso have such downstream detector 72 b. It is contemplated to configurecontrol unit 12, such that the pump actuator 20 and associated valveactuators 16 a and 16 b are allowed to continue to pump the drug ormedication to the patient until the air detected by downstream sensor 72b is calculated to be close to the infusion site. The program oralgorithm saved in control unit 12 can take into account a knownflowrate, tubing diameter, tubing length and location of the activatedair detector 72 b relative to the infusion site. Such structure andmethodology again maximizes the time that the drug is delivered to thepatient, while maintaining safety.

Additional Aspects of the Present Disclosure

Aspects of the subject matter described herein may be useful alone or incombination one or more other aspect described herein. Without limitingthe foregoing description, in a first aspect of the present disclosure,an intravenous (“IV”) liquid delivery system includes an IV pump tubingset; a pump actuator operable with the IV pump tubing set; and an airremoval device located upstream of the pump actuator, the air removaldevice including a liquid inlet, a liquid outlet, an air collectionportion, and a liquid collection portion located adjacent to the liquidoutlet, and wherein the air collection portion of the air removal deviceincludes an air passing but liquid retaining filter and a check valve inair flow communication with the air passing but liquid retaining filter.

In accordance with a second aspect of the present disclosure, which maybe used in combination with the first aspect, the IV pump tubing setincludes an upstream valve portion, a downstream valve portion and apump portion located between the upstream and downstream valve portions,the system further including upstream and downstream valve actuatorsoperable with the pump actuator to move liquid through the IV pumptubing set.

In accordance with a third aspect of the present disclosure, which maybe used in combination with the second aspect, the air removal device islocated upstream of the upstream valve portion.

In accordance with a fourth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the filter is a hydrophobic filter.

In accordance with a fifth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the liquid collection portion includes a liquid passing but air retainerfilter.

In accordance with a sixth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the IV pump tubing set is configured to be mounted such that the aircollection portion is located elevationally above the liquid collectionportion.

In accordance with a seventh aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the air removal device includes a housing having a largercross-sectional area than that of a tube of the IV pump tubing set.

In accordance with an eighth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the air removal device is provided as part of the IV pump tubing set.

In accordance with a ninth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects,the IV liquid delivery system includes at least one air detector locateddownstream of the air removal device.

In accordance with a tenth aspect of the present disclosure, which maybe used in combination with any one or more of the preceding aspects, anintravenous (“IV”) liquid delivery system includes an IV pump tubingset; a pump actuator operable with the IV pump tubing set; an airremoval device located downstream of the pump actuator, the air removaldevice including an air passing but liquid retaining filter and a liquidpassing but air retaining filter; a device that indicates that the airremoval device is present; and a control unit operable with theindicting device, the control unit configured so that when the airremoval device is indicated as being present, the pump actuator isallowed to operate the IV pump tubing set even if air is detectedupstream of the air removal device.

In accordance with an eleventh aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the tenth aspect, the IV liquid delivery system includes an airdetector located downstream of the pump actuator, and wherein thecontrol unit is further configured to stop the pump actuator if air isdetected at the downstream air detector.

In accordance with a twelfth aspect of the present disclosure, which maybe used with any one or more of the preceding aspects in combinationwith the tenth aspect, the control unit is further configured so thatwhen the air removal device is indicated as not being present, the pumpactuator is stopped if air is detected upstream of the air removaldevice.

In accordance with a thirteenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the tenth aspect, the indicting device includes a sensor positionedto sense the presence of the air removal device.

In accordance with a fourteenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the tenth aspect, the indicting device includes a code providedwith one of the IV pump tubing set and the air removal device.

In accordance with a fifteenth aspect of the present disclosure, whichmay be used in combination with any one or more of the precedingaspects, an intravenous (“IV”) liquid delivery system includes an IVpump tubing set; a pump actuator operable with the IV pump tubing set;an upstream valve actuator operable with the IV pump tubing set upstreamof the pump actuator; a downstream valve actuator operable with the IVpump tubing set downstream of the pump actuator; an air purge valveactuator operable with the IV pump tubing set downstream of thedownstream valve actuator; and an air removal device located between thedownstream valve actuator and the air purge valve actuator, the systemconfigured to close the air purge valve actuator to force air in the IVpump tubing set to be purged through the air removal device.

In accordance with a sixteenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the fifteenth aspect, the pump actuator is a shuttle pump actuator,the shuttle pump or membrane pump actuator operable with the upstreamand downstream valve actuators to move liquid through the IV pump tubingset.

In accordance with a seventeenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the fifteenth aspect, the air removal device includes an airpassing but liquid retaining filter.

In accordance with an eighteenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the fifteenth aspect, the IV liquid delivery system is configuredand arranged to close the air purge valve actuator for a time or anumber of pump-out strokes sufficient to force air in the IV pump tubingset to be purged through the air removal device.

In accordance with a nineteenth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the fifteenth aspect, the IV pump tubing set includes the airremoval device positioned between a downstream valve actuator portion ofthe IV pump tubing set and an air purge valve actuator portion of the IVpump tubing set.

In accordance with a twentieth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the fifteenth aspect, the IV liquid delivery system is configuredand arranged to maintain open the air purge valve actuator and sequencethe pump, upstream and downstream valve actuators for pumping.

In accordance with a twenty-first aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the fifteenth aspect, the IV liquid delivery systemincludes at least one air detector located upstream or downstream of thepump actuator.

In accordance with a twenty-second aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the fifteenth aspect, the air removal device extendsoff of a primary liquid delivery line of the IV pump tubing set.

In accordance with a twenty-third aspect of the present disclosure,which may be used in combination with any one or more of the precedingaspects, an intravenous (“IV”) liquid delivery system includes an IVpump tubing set; a pump actuator operable with the IV pump tubing set;an upstream valve actuator operable with the IV pump tubing set upstreamof the pump actuator; an air detector located upstream of the upstreamvalve actuator; a downstream valve actuator operable with the IV pumptubing set downstream of the pump actuator; and an air purge valveactuator operable with the IV pump tubing set downstream of thedownstream valve actuator, wherein the IV pump tubing set furtherincludes a bypass recirculation line extending from a point locatedbetween the downstream valve actuator and the air purge valve actuatorto a point in the IV pump tubing set upstream of the air detector, andwherein upon a detection of air in a medical fluid by the air detector,the air purge valve actuator is closed and the pump actuator, theupstream valve actuator and the downstream valve actuator are operatedto recirculate the medical fluid using the bypass recirculation line topurge air from the medical fluid.

In accordance with a twenty-fourth aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the twenty-third aspect, the bypass recirculation lineextends to a supply of the medical fluid for the IV pump tubing set.

In accordance with a twenty-fifth aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the twenty-third aspect, the bypass recirculation lineis in fluid communication with an air removal device to purge air fromthe medical fluid.

In accordance with a twenty-sixth aspect of the present disclosure,which may be used in combination with any one or more of the precedingaspects, an intravenous (“IV”) liquid delivery system includes an IVpump tubing set; a pump actuator operable with the IV pump tubing set;and an air removal device located downstream of the pump actuator, theair removal device including (i) a housing having an inlet end and anoutlet end, (ii) a first potted member located adjacent the inlet end,(iii) a second potted member located adjacent the outlet end, and (iv) aplurality of air passing but liquid retaining hollow fibers extendingfrom the first potted member to the second potted member, whereinmedical fluid potentially entraining air is passed through the hollowfibers so as to provide a path of least resistance radially out of thehollow fibers.

In accordance with a twenty-seventh aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the twenty-sixth aspect, the IV liquid delivery systemincludes an air detector located upstream of the pump actuator, the airdetector used for at least one of (a) providing an air sense alert and(b) providing a signal used to integrate air volume through the IV pumptubing set.

In accordance with a twenty-eighth aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the twenty-sixth aspect, the IV liquid delivery systemincludes an air detector located downstream of the air removal device,the air detector used to shut down the system in case air in the IV pumptubing set escapes the air removal device.

In accordance with a twenty-ninth aspect of the present disclosure,which may be used with any one or more of the preceding aspects, anintravenous (“IV”) liquid delivery system includes an IV pump tubingset; a shuttle pump or membrane pump actuator operable with the IV pumptubing set; an upstream valve actuator operable with the IV pump tubingset; a downstream valve actuator operable with the IV pump tubing set;the IV pump tubing set including an air removal device; an air detectorconfigured to sense air in the IV pump tubing set; a control unitconfigured and arranged to (i) open the upstream valve actuator andclose the downstream valve actuator to allow the pump actuator to drawliquid into a pump actuation portion of the IV pump tubing set, and (ii)close the upstream valve actuator and open the downstream valve actuatorto allow the pump actuator to push liquid out of the pump actuationportion; and wherein the system is configured to attempt to remove theair via the air removal device while operating the upstream anddownstream valve actuators according to (i) and (ii).

In accordance with a thirtieth aspect of the present disclosure, whichmay be used with any one or more of the preceding aspects in combinationwith the twenty-ninth aspect, the air removal device is located (a)upstream of the upstream valve actuator or (b) downstream of the pumpactuator.

In accordance with a thirty-first aspect of the present disclosure,which may be used with any one or more of the preceding aspects incombination with the twenty-ninth aspect, the IV liquid delivery systemincludes (a) an air detector and (b) an air purge valve actuator locateddownstream of the downstream valve actuator, the control unit furtherconfigured to receive a signal from the air detector indicative of airin the IV pump tubing set and close the air purge valve actuator toattempt to remove the air via the air removal device while operating theupstream and downstream valve actuators according to (i) and (ii).

In accordance with a thirty-second aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 1 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-third aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 2 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-fourth aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 3 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-fifth aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 4 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-sixth aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 5 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-seventh aspect of the present disclosure,any of the structure and functionality illustrated and described inconnection with FIG. 6 may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-eighth aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 7A may be used in combination with any one or moreof the preceding aspects.

In accordance with a thirty-ninth aspect of the present disclosure, anyof the structure and functionality illustrated and described inconnection with FIG. 7B may be used in combination with any one or moreof the preceding aspects.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. An intravenous (“IV”) liquiddelivery system comprising: an IV pump tubing set; a pump actuatoroperable with the IV pump tubing set; an upstream valve actuatoroperable with the IV pump tubing set upstream of the pump actuator; adownstream valve actuator operable with the IV pump tubing setdownstream of the pump actuator; an air purge valve actuator operablewith the IV pump tubing set downstream of the downstream valve actuator;and an air removal device located between the downstream valve actuatorand the air purge valve actuator; at least one air detector fordetecting air in the IV pump tubing set; and the system configured, uponreceipt of a signal indicating air from the at least one air detector,to (i) close the air purge valve actuator, and (ii) force air in the IVpump tubing set to be purged through the air removal device.
 2. The IVliquid delivery system of claim 1, wherein the pump actuator includes ashuttle pump or membrane pump actuator, the shuttle pump or membranepump actuator operable with the upstream and downstream valve actuatorsto move liquid through the IV pump tubing set.
 3. The IV liquid deliverysystem of claim 1, wherein the air removal device includes an airpassing but liquid retaining filter.
 4. The IV liquid delivery system ofclaim 1, which is configured and arranged to close the air purge valveactuator for a time or a number of pump-out strokes sufficient to forceair in the IV pump tubing set to be purged through the air removaldevice.
 5. The IV liquid delivery system of claim 1, wherein the IV pumptubing set includes the air removal device positioned between adownstream valve actuator portion of the IV pump tubing set and an airpurge valve actuator portion of the IV pump tubing set.
 6. The IV liquiddelivery system of claim 1, which is configured and arranged to maintainopen the air purge valve actuator and sequence the pump, upstream anddownstream valve actuators for pumping.
 7. The IV liquid delivery systemof claim 1, wherein the at least one air detector is located upstream ordownstream of the pump actuator for detecting air in the IV pump tubingset.
 8. The IV liquid delivery system of claim 1, wherein the at leastone air detector is located upstream of the upstream valve actuator fordetecting air in the IV pump tubing set.
 9. The IV liquid deliverysystem of claim 1, wherein the air removal device extends off of aprimary liquid delivery line of the IV pump tubing set.
 10. The IVliquid delivery system of claim 1, wherein the control unit is furtherconfigured upon receipt of the signal from the at least one airdetector, to cause the pump actuator to perform at least one pump-outstroke.
 11. An intravenous (“IV”) liquid delivery system comprising: anIV pump tubing set; a pump actuator operable with the IV pump tubingset; an upstream valve actuator operable with the IV pump tubing setupstream of the pump actuator; a downstream valve actuator operable withthe IV pump tubing set downstream of the pump actuator; an air purgevalve actuator operable with the IV pump tubing set downstream of thedownstream valve actuator; and an air removal device located between thedownstream valve actuator and the air purge valve actuator; at least oneair detector for detecting air in the IV pump tubing set; and a controlunit configured, upon receipt of a signal indicating air from the atleast one air detector, to (i) close the air purge valve actuator, and(ii) force air in the IV pump tubing set to be purged through the airremoval device.